Mark Madoff, 46, was found hanging from a ceiling pipe in the living room of his SoHo loft apartment as his 2-year-old son slept in a nearby bedroom, two law enforcement officials told The Associated Press.
Madoff, who reported his father to authorities, has never been criminally charged in the biggest investment fraud in U.S. history, that has snared a half-dozen Madoff employees.
Mark Madoff and his brother Andrew have said they were unaware of their father's crimes. But they have been remained under investigation and been named in multiple investor lawsuits accusing them of profiting from the scheme.
But a third law enforcement official said Sautrday that Madoff's arrest was not imminent, and that investigators purusing possible charges against him, his brother and uncle hadn't contacted him for more than a year. The official wasn't authorized to speak publicly about the case and spoke on condition of anonymity.
Mark Madoff killed himself on Saturday, said his lawyer, Martin Flumenbaum.
"This is a terrible and unnecessary tragedy," Flumenbaum said in a written statement. "Mark was an innocent victim of his father's monstrous crime who succumbed to two years of unrelenting pressure from false accusations and innuendo."
A lawyer for Mark's mother, Ruth Madoff, said, "She's heartbroken." The lawyer, Peter Chavkin, had no further comment.
The law enforcement officials, speaking on condition of anonymity because they weren't authorized to speak publicly about the death.
Bernard Madoff, 72, swindled a long list of investors out of billions of dollars. He admitted that he ran his scheme for at least two decades, cheating thousands of individuals, charities, celebrities and institutional investors. Losses are estimated at around $20 billion, making it the biggest investment fraud in U.S. history.
He was arrested on Dec. 11, 2008, after confessing his crimes to his family.
The scandal put a harsh light on members of the family. The financier's brother, Peter, played a prominent role in the family's company. Mark and Andrew Madoff both worked on a trading desk at the firm, on a side of the business that wasn't directly involved in the Ponzi scheme.
In February, Mark Madoff's wife petitioned a court to change her last name and the last names of their two children, saying her family had gotten threats and was humiliated by the scandal.
A year ago, the court-appointed trustee trying to unravel Madoff's financial affairs sued several relatives, including Peter, Mark and Andrew, accusing them of failing to detect the fraud while living lavish lifestyles financed with the family's ill-gotten fortune.
The lawsuit accused Mark Madoff of using $66 million he received improperly to buy luxury homes in New York City, Nantucket and Connecticut.
A call to Bernard Madoff's attorney was not immediately returned Saturday. Calls to the FBI and U.S. Attorney's office were also not immediately returned. Previously, spokespeople for the brothers had repeatedly denied that they had any knowledge of their father's crimes.
Bernard Madoff is serving a 150-year prison sentence in North Carolina. Bureau of Prisons spokeswoman Traci Billingsley said Saturday she didn't have specific information on whether Bernie Madoff had been informed of his son's death or would be allowed to attend a service. In general, she said, inmates are informed of a relative's death as soon as the institution is made aware of it and the bureau does allow furloughs for prisoners to attend memorial services.
A police officer stood guard in the lobby of Madoff's 12-story luxury loft apartment in SoHo Saturday morning.
The building sits on a busy block abutting Broadway in an area crowded with clothing botiques, cafes and art galleries. The sidewalks and cobblestone streets near the apartment were packed with Christmas shoppers Saturday, as dozens of reporters stood vigil.
Bystanders gawked as officials from the medical examiner's office removed the body early Saturday afternoon. The medical examiner will determine the cause of death.